Hybrid beamforming has attracted considerable attention in recent years as an efficient and promising technique for the practical implementation of millimeter-Wave (mmWave) massive multiple-input multiple-output (MIMO) wireless systems. In this paper, we investigate hybrid analog/digital beamforming designs based on a single RF chain architecture (SRCA) for mmWave massive-MIMO. We first revisit the SRCA and then explore its shortcomings. Subsequently, we present three novel beamformer designs which achieve the performance of fully-digital precoding systems while eliminating the drawbacks of SRCA. We further explore the applications of these designs for optimal precoding in both single-user and multiuser scenarios. Finally, we present simulation results which confirm the superiority of our proposed designs to recently published works.